Question: How many cubic inches fit in $5$ cubic feet?
Answer: First we will figure out how many cubic inches fit in one cubic foot. There are $12$ inches in every foot. So a cubic foot is the same as a $ 12 \text{ in} \times 12 \text{ in} \times12 \text{ in} $ cube. $1 \text{ft} = 12 \text{in}$ There are $12 \times 12 \times 12 = 1728 \text{ in}^3 $ in each cubic foot, by the volume formula. Since we have $5$ cubic feet, and each cubic foot holds $1728$ cubic inches, we have a total of $5 \times 1728$ cubic inches. So $8640$ cubic inches fit in $5$ cubic feet.